The School Building Committee heard about plans for essential systems in the new elementary school last week, with an emphasis on energy savings and technology that has changed since 1988, when the current school was built. Carlos DeSousa, of the engineering firm Garcia, Galuska, & DeSousa, described plans for HVAC (heating, ventilation, and air conditioning), plumbing, lighting, and technology.
The ventilation system in the new building will be “just the opposite of what is in this room now,” DeSousa told committee members as they sat in the Bromfield School library Oct. 4. Instead of using ceiling vents to bring in outside air, rooms in the new building will have fresh-air vents down at the occupants’ level, with exhaust vents in the ceiling. The focus is on air quality and comfort from the floor up to 6 feet, he said.
In cold weather, hot water from a gas boiler will circulate through radiant wall panels to heat the building. In warm weather, air in the classrooms and gym will be dehumidified but not air-conditioned. Air-conditioning will be limited to areas in use year-round, mainly the offices.
Committee member Ron Ostberg pointed out that the number of days with temperatures in the 90s is increasing year by year, and he asked how the committee should plan for the building’s expected 50-year lifespan. Tom Ryan, the project manager, suggested making the rooftop space for the chiller large enough to allow for a bigger unit in the future, if it is needed. In that case, a larger chiller could provide cold water through the same radiant panels to make classrooms cooler.
All the lighting in the new building will use LEDs, DeSousa said, reducing lighting to 15 percent of the school’s energy use. (In older schools, lighting sometimes accounted for as much as 60 percent of energy use, he said.) Occupancy sensors will turn lights down or off when the room is empty and when daylight is sufficient. A mix of direct and indirect lighting will help reduce both shadows and glare.
The plumbing system will use water-conserving fixtures, including flush valves that have battery-powered sensors. The action of the flushing water turns a turbine that charges the battery, which keeps the system working even if power goes out, DeSousa said. But toilets in the kindergarten and pre-K rooms will have handles for flushing, because younger children sometimes find automatic flushes scary.
In planning for technology use in the building, DeSousa warned that last-minute change orders can be costly, and it was important to allow flexibility for changes that will occur in the next three years.